From 3ffa1af11e0eda10a6355f5423ab5432345c67d4 Mon Sep 17 00:00:00 2001
From: Isaac Roberts <119639439+madebyisaacr@users.noreply.github.com>
Date: Thu, 9 Apr 2026 13:08:06 -0400
Subject: [PATCH 1/2] Sync up to 100 relation values

---
 plugins/notion/src/api.ts  | 24 ++++++++++++++++++++++++
 plugins/notion/src/data.ts | 19 ++++++++++++++-----
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/plugins/notion/src/api.ts b/plugins/notion/src/api.ts
index f542ab766..adfb37046 100644
--- a/plugins/notion/src/api.ts
+++ b/plugins/notion/src/api.ts
@@ -2,6 +2,7 @@ import { Client, collectPaginatedAPI, isFullBlock, isFullDatabase, isFullPage }
 import type {
     BlockObjectResponse,
     GetDatabaseResponse,
+    GetPagePropertyResponse,
     PageObjectResponse,
     RichTextItemResponse,
 } from "@notionhq/client/build/src/api-endpoints"
@@ -405,6 +406,29 @@ export async function getPageBlocksAsRichText(pageId: string) {
     return blocksToHtml(blocks)
 }
 
+const RELATION_PROPERTY_PAGE_SIZE = 100
+
+/**
+ * Loads up to {@link RELATION_PROPERTY_PAGE_SIZE} related page ids when the relation is truncated on
+ * retrieve-page / query (has_more). Does not paginate past the first page.
+ */
+export async function fetchRelationIdsForPageProperty(pageId: string, propertyId: string): Promise<string[]> {
+    const notion = getNotionClient()
+    const response = await notion.pages.properties.retrieve({
+        page_id: pageId,
+        property_id: propertyId,
+        page_size: RELATION_PROPERTY_PAGE_SIZE,
+    })
+
+    if (response.object === "list") {
+        return response.results.flatMap(item => (item.type === "relation" ? [item.relation.id] : []))
+    }
+    if (response.type === "relation") {
+        return [response.relation.id]
+    }
+    return []
+}
+
 export async function getDatabaseItems(
     database: GetDatabaseResponse,
     onProgress?: (progress: { current: number; total: number; hasFinishedLoading: boolean }) => void
diff --git a/plugins/notion/src/data.ts b/plugins/notion/src/data.ts
index 039470991..1f3ff7304 100644
--- a/plugins/notion/src/data.ts
+++ b/plugins/notion/src/data.ts
@@ -13,6 +13,7 @@ import {
     alwaysSyncedPropertyTypes,
     assertFieldTypeMatchesPropertyType,
     type FieldInfo,
+    fetchRelationIdsForPageProperty,
     getDatabase,
     getDatabaseFieldsInfo,
     getDatabaseItems,
@@ -241,7 +242,7 @@ export async function syncCollection(
                     continue
                 }
 
-                const fieldEntry = getFieldDataEntryForProperty(property, field)
+                const fieldEntry = await getFieldDataEntryForProperty(property, field, item.id)
                 if (fieldEntry) {
                     fieldData[field.id] = fieldEntry
                 } else {
@@ -624,10 +625,11 @@ export function fieldsInfoToCollectionFields(
     return fields
 }
 
-export function getFieldDataEntryForProperty(
+async function getFieldDataEntryForProperty(
     property: PageObjectResponse["properties"][string],
-    field: ManagedCollectionFieldInput
-): FieldDataEntryInput | null {
+    field: ManagedCollectionFieldInput,
+    itemId: string
+): Promise<FieldDataEntryInput | null> {
     switch (property.type) {
         case "checkbox": {
             return { type: "boolean", value: property.checkbox }
@@ -691,7 +693,14 @@ export function getFieldDataEntryForProperty(
         }
         case "relation": {
             if (field.type === "multiCollectionReference") {
-                return { type: "multiCollectionReference", value: property.relation.map(({ id }) => id) }
+                let relationItemIds: string[] = []
+                if ("has_more" in property && property.has_more) {
+                    relationItemIds = await fetchRelationIdsForPageProperty(itemId, property.id)
+                } else {
+                    relationItemIds = property.relation.map(({ id }) => id)
+                }
+
+                return { type: "multiCollectionReference", value: relationItemIds }
             } else if (field.type === "collectionReference") {
                 return { type: "collectionReference", value: property.relation[0]?.id ?? null }
             }

From ae6d9830e5eedb3b61a51bcaf0da5adb60210a00 Mon Sep 17 00:00:00 2001
From: Isaac Roberts <119639439+madebyisaacr@users.noreply.github.com>
Date: Thu, 9 Apr 2026 13:36:08 -0400
Subject: [PATCH 2/2] Improve code, remove unused type

---
 plugins/notion/src/api.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/plugins/notion/src/api.ts b/plugins/notion/src/api.ts
index adfb37046..24aa81984 100644
--- a/plugins/notion/src/api.ts
+++ b/plugins/notion/src/api.ts
@@ -2,7 +2,6 @@ import { Client, collectPaginatedAPI, isFullBlock, isFullDatabase, isFullPage }
 import type {
     BlockObjectResponse,
     GetDatabaseResponse,
-    GetPagePropertyResponse,
     PageObjectResponse,
     RichTextItemResponse,
 } from "@notionhq/client/build/src/api-endpoints"
@@ -421,7 +420,7 @@ export async function fetchRelationIdsForPageProperty(pageId: string, propertyId
     })
 
     if (response.object === "list") {
-        return response.results.flatMap(item => (item.type === "relation" ? [item.relation.id] : []))
+        return response.results.map(item => (item.type === "relation" ? item.relation.id : "")).filter(id => id !== "")
     }
     if (response.type === "relation") {
         return [response.relation.id]